From: dan <dan@noemail.net>
Date: Mon, 25 Mar 2013 16:28:54 +0000 (+0000)
Subject: Remove unnecessary code to round the size of a memory mapping to 4KB from os_unix... 
X-Git-Tag: version-3.7.17~114^2~46
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=aef49d7141d9bbbc68a2c8ce7bd17cdafb06aa6b;p=thirdparty%2Fsqlite.git

Remove unnecessary code to round the size of a memory mapping to 4KB from os_unix.c. Rename SQLITE_IOERR_MREMAP to SQLITE_IOERR_MMAP. Fix other small issues in os_unix.c.

FossilOrigin-Name: dce35c01a5fe66d2970075b1e3f0376026485e4c
---

diff --git a/manifest b/manifest
index 01d74c7724..919b150ea9 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Do\snot\sreturn\sSQLITE_IOERR\swhen\sthe\suser\sattempts\sto\sopen\sa\ssmall\sfile\sthat\sis\snot\sa\sdatabase\swith\smmap\senabled.\sInstead\sreturn\sSQLITE_NOTADB.
-D 2013-03-25T14:31:39.689
+C Remove\sunnecessary\scode\sto\sround\sthe\ssize\sof\sa\smemory\smapping\sto\s4KB\sfrom\sos_unix.c.\sRename\sSQLITE_IOERR_MREMAP\sto\sSQLITE_IOERR_MMAP.\sFix\sother\ssmall\sissues\sin\sos_unix.c.
+D 2013-03-25T16:28:54.437
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 9a804abbd3cae82d196e4d33aba13239e32522a5
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -160,7 +160,7 @@ F src/notify.c 976dd0f6171d4588e89e874fcc765e92914b6d30
 F src/os.c a7ec2ddc43fb2684bfd8cb30db15ea6cce3298e9
 F src/os.h 782980cd0d840b4240a6e29ba9f8ef0ca0d750ca
 F src/os_common.h 92815ed65f805560b66166e3583470ff94478f04
-F src/os_unix.c 1e61abcb664f3430ce13e5c5f32b2b2e204a6f23
+F src/os_unix.c 82efc58c818c69e191f5560935037af365f99ff5
 F src/os_win.c 386f8c034b177b672f7819ddc5d80be6c8d593ac
 F src/pager.c 2dd59f366b519d01d08b44f615058e7cfacd0bd7
 F src/pager.h 241d72dc0905df042da165f086d03505cb0bb50c
@@ -176,7 +176,7 @@ F src/resolve.c 9079da7d59aed2bb14ec8315bc7f720dd85b5b65
 F src/rowset.c 64655f1a627c9c212d9ab497899e7424a34222e0
 F src/select.c e1c6f6abdf9f359f4e735cb8ae11d2f359bf52a9
 F src/shell.c 7c41bfcd9e5bf9d96b9215f79b03a5b2b44a3bca
-F src/sqlite.h.in f41949e1e778043dd9fc23b33b96e7a6e20de4d6
+F src/sqlite.h.in a0866dafaa412d1e89abbc78d2b44b12cf95d1d1
 F src/sqlite3.rc fea433eb0a59f4c9393c8e6d76a6e2596b1fe0c0
 F src/sqlite3ext.h 7183ab832e23db0f934494f16928da127a571d75
 F src/sqliteInt.h 2c3d830ae78b046ebf939c905c023610e43c2796
@@ -1039,7 +1039,7 @@ F tool/vdbe-compress.tcl f12c884766bd14277f4fcedcae07078011717381
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
 F tool/win/sqlite.vsix 97894c2790eda7b5bce3cc79cb2a8ec2fde9b3ac
-P 5885ba6ce768658ec25b60747430d147b315b55c
-R c243df2223b3431445e14c1469df7b20
+P bbcaab3e80d0ff776d8567094b137d1483b3377b
+R fd25f18074b1cc787a38214a338c9127
 U dan
-Z 6b851eca8762089c75296a1160d8987e
+Z ae05d407cd866087491e3302af269873
diff --git a/manifest.uuid b/manifest.uuid
index b4cdb9d207..23ee7e3b08 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-bbcaab3e80d0ff776d8567094b137d1483b3377b
\ No newline at end of file
+dce35c01a5fe66d2970075b1e3f0376026485e4c
\ No newline at end of file
diff --git a/src/os_unix.c b/src/os_unix.c
index d865810570..a97aba87f1 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -4493,15 +4493,8 @@ static int unixShmUnmap(
 #endif /* #ifndef SQLITE_OMIT_WAL */
 
 /*
-** Arguments x and y are both integers. Argument y must be a power of 2.
-** Round x up to the nearest integer multiple of y. For example:
-**
-**     ROUNDUP(0,  8) ->  0
-**     ROUNDUP(13, 8) -> 16
-**     ROUNDUP(32, 8) -> 32
+** If it is currently memory mapped, unmap file pFd.
 */
-#define ROUNDUP(x,y)     (((x)+y-1)&~(y-1))
-
 static void unixUnmapfile(unixFile *pFd){
   assert( pFd->nFetchOut==0 );
   if( pFd->pMapRegion ){
@@ -4512,6 +4505,22 @@ static void unixUnmapfile(unixFile *pFd){
   }
 }
 
+/*
+** Memory map or remap the file opened by file-descriptor pFd (if the file
+** is already mapped, the existing mapping is replaced by the new). Or, if 
+** there already exists a mapping for this file, and there are still 
+** outstanding xFetch() references to it, this function is a no-op.
+**
+** If parameter nByte is non-negative, then it is the requested size of 
+** the mapping to create. Otherwise, if nByte is less than zero, then the 
+** requested size is the size of the file on disk. The actual size of the
+** created mapping is either the requested size or the value configured 
+** using SQLITE_FCNTL_MMAP_SIZE, whichever is smaller.
+**
+** SQLITE_OK is returned if no error occurs (even if the mapping is not
+** recreated as a result of outstanding references) or an SQLite error
+** code otherwise.
+*/
 static int unixMapfile(unixFile *pFd, i64 nByte){
   i64 nMap = nByte;
   int rc;
@@ -4538,19 +4547,32 @@ static int unixMapfile(unixFile *pFd, i64 nByte){
       void *pNew;
       int flags = PROT_READ;
       if( (pFd->ctrlFlags & UNIXFILE_RDONLY)==0 ) flags |= PROT_WRITE;
-      pNew = mmap(0, ROUNDUP(nMap, 4096), flags, MAP_SHARED, pFd->h, 0);
+      pNew = mmap(0, nMap, flags, MAP_SHARED, pFd->h, 0);
       if( pNew==MAP_FAILED ){
-        return SQLITE_IOERR_MREMAP;
+        return SQLITE_IOERR_MMAP;
       }
 
       pFd->pMapRegion = pNew;
-      pFd->mmapOrigsize = pFd->mmapSize = nMap;
+      pFd->mmapSize = nMap;
+      pFd->mmapOrigsize = nMap;
     }
   }
 
   return SQLITE_OK;
 }
 
+/*
+** If possible, return a pointer to a mapping of file fd starting at offset
+** iOff. The mapping must be valid for at least nAmt bytes.
+**
+** If such a pointer can be obtained, store it in *pp and return SQLITE_OK.
+** Or, if one cannot but no error occurs, set *pp to 0 and return SQLITE_OK.
+** Finally, if an error does occur, return an SQLite error code. The final
+** value of *pp is undefined in this case.
+**
+** If this function does return a pointer, the caller must eventually 
+** release the reference by calling unixUnfetch().
+*/
 static int unixFetch(sqlite3_file *fd, i64 iOff, int nAmt, void **pp){
   unixFile *pFd = (unixFile *)fd;   /* The underlying database file */
   *pp = 0;
@@ -4568,9 +4590,19 @@ static int unixFetch(sqlite3_file *fd, i64 iOff, int nAmt, void **pp){
   return SQLITE_OK;
 }
 
+/*
+** If the second argument is non-NULL, then this function releases a 
+** reference obtained by an earlier call to unixFetch(). Or, if the second
+** argument is NULL, then this function is being called to inform the VFS
+** layer that, according to POSIX, any existing mapping may now be invalid
+** and should be unmapped.
+*/
 static int unixUnfetch(sqlite3_file *fd, void *p){
   unixFile *pFd = (unixFile *)fd;   /* The underlying database file */
 
+  /* If p==0 (unmap the entire file) then there must be no outstanding 
+  ** xFetch references. Or, if p!=0 (meaning it is an xFetch reference),
+  ** then there must be at least one outstanding.  */
   assert( (p==0)==(pFd->nFetchOut==0) );
 
   if( p ){
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 666a2e084d..7bbd3fa000 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -470,7 +470,7 @@ int sqlite3_exec(
 #define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
 #define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
 #define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
-#define SQLITE_IOERR_MREMAP            (SQLITE_IOERR | (24<<8))
+#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
 #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
 #define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
 #define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))